BRPI0620722A2 - method and device for producing curved spring elements - Google Patents

Abstract

The invention is based on a method of producing bent spring elements from a spring steel strip (14), wherein a feed unit (16) delivers the spring steel strip (14) from a supply roll (12) to a bending unit (32) having at least three bending rollers (34) and a reverse bending roller (36), of which at least one bending roller (34) and the reverse bending roller (36) can be adjusted transversely to the spring steel strip (14) by bending motors (60, 62), and wherein a cutting-off unit (44) adjoins the bending unit (32), said cutting-off unit (44) cutting off the spring steel strip (14) into individual spring elements by means of cutting-off tools (46, 48; 76, 78). It is proposed that the cutting-off tools (46, 48; 76, 78) be movable in the longitudinal direction of the spring steel strip (14) in a numerically controlled manner and that they be synchronized with the feed movement of the spring steel strip (14) during the cutting-off operation.

Description

Report of the Invention Patent for "METHOD AND DEVICE FOR THE PRODUCTION OF CURVED SPRING ELEMENTS".

State of the Art

The present invention relates to a method and a device for producing curved spring elements according to the preambles of claims 1 and 2.

From DE 198 16 609 A1 there is known a method and a device for producing flat beam windshield wipers for cars with curved spring elements, called flat beams. These form the support element of the windshield wiper blade and preferably have a material thickness that varies along the length. They are made from a spring steel strip that is supplied to a continuous feed bending unit by two paired feed rollers via guide rollers. The curving unit comprises a separation unit through which the individual support elements are separated from each other after being curved. During the separation process, continuous feed is temporarily interrupted.

In the bending unit the spring steel strip is first bent in one direction by three contact points, and through a next contact point, is slightly bent in reverse. The degree of inverse curvature that is required to ensure the shape stability of the curved support member is obtained empirically. Depending on the quality of the spring steel strip, an average value of about 10% to 40% of the previous curvature previously made was consecrated. The first two contact points in the transport direction of the bending unit are bending rollers, while the third contact point is a cutting edge that cooperates with a cutting knife and which secures the definitely bent support element. of the steel tape for milling. The bending rollers may be displaced by servomotors approaching the spring steel strip and moving away from the spring steel strip. According to the position of the bending rollers a predetermined bending of the spring steel strip is produced. The servomotors are activated by an electronic control unit due to various influence values, controlled by program.

DE 101 15 047 A1 also discloses a method and device for producing curved segments from spring steel tape. The device comprises a feed unit that carries a spring steel strip from a spare roll to a bend unit. Between the feed unit and the bend unit, a straightening device is provided. The bending unit comprises three bending rollers and one reverse bending roll of which a bending roll and the reverse bending roll can be adjusted by an adjusting device transversely to the spring steel strip. The bending unit is followed by a separation unit that is connected to the NC control unit and separates the steel strip segments for individual springs. During the separation process, the advance of the spring steel strip is temporarily stopped.

The Advantages of the Present Invention

In accordance with the present invention, the advance of the spring steel strip is not interrupted. This is possible because the separation tools can be moved longitudinally from the spring steel strip in a numerically controlled manner and during the separation process they are synchronized with the forward movement of the spring steel strip. The uniform feed rate also produces in the bending unit a uniform bending process which has a positive influence on the properties of the curved spring elements. In contrast, known devices work with a starting system - stopping at very different speeds and high accelerations during a feed and bending process, especially when large numbers of units per unit of time must be produced. Intermittent feed causes stress on components and causes increased wear. Due to the continuous advancement the drive motors co-operate better with each other, so that less wear occurs and higher performance becomes possible. In addition, for process control, so-called trigger holes in the spring steel tape can be dispensed with. These can cause large differences in length and inaccuracies in curvature.

In a device for carrying out the method, the separation tools in longitudinal direction of the forward movement of the spring steel strip are arranged adjustable relative thereto, and their adjusting movement is synchronized by a control unit. during the separation process with the forward movement of the spring steel strip. It is therefore possible that the sorting tools together with the sorting unit in longitudinal direction of the spring steel strip feed motion are adjustable with respect to this, or that the sorting tools are arranged in one direction. fixed housing of the separating unit, where they can be adjusted relative to the housing and in the longitudinal direction of the forward movement of the spring steel strip relative thereto. The second alternative is simpler to perform and the separation tools can be activated with greater precision.

To guide the spring steel tape between the bending unit and the separation tools, a roller guide is used which rollers can be pneumatically adjusted to the spring steel tape. It is also appropriate that some guide rollers in the longitudinal direction separation tool area may change their position relative to each other, so that the distances between them increase or decrease as the longitudinal direction of the separation tools move. . Due to the adjustment of the separation tools in longitudinal direction of the spring steel strip, different distances appear between the bending unit and the separation tools. Therefore, it is advantageous when some guide rollers can adapt to this different distance and distribute without excessive spans along the distance.

In order to be able to produce many different lengths and curvatures it is appropriate to arrange the separation tools in a stationary box, where a defined zero position is determined for the separation tools moving in longitudinal direction. In order to be able to adjust the bending unit to the respective type of spring elements at the zero point of the separation unit, it is appropriate to configure these also adjustable in longitudinal direction. During device preparation. adjustment for a spring element type can be done manually. Advantageously motor adjustment can also be made by means of a spindle drive. This way you can include the adjustment in an automatic preparation process. In addition, it is useful not only to adjust the bending unit in the longitudinal direction, but to join the bending unit with the feed unit and at least one feed unit and at least one NC measuring wheel to form a building unit. adjustable in longitudinal direction.

To achieve accurate bends, the adjustable bend rollers or reverse bend roll paths must be set exactly. To do this, adjust the bending roller brackets where the bending rollers are supported by bending motors by means of widely free play spindles. In this way, the travel path or the adjustment path can be determined by taking into account the preliminary values of an electronic control unit via a rotating increment emitter when the bending motors are, for example, CNC bending motors. The travel path of the bend roller supports can also be advantageously determined by means of a software-integrated absolute value transmitter. This may comprise, for example, a glass scale with a sensor. It is suitable for both CNC bending motors and also for bending motors that run as linear motors.

For the removal of the finished spring elements it is advantageous that the separation unit is followed by a discharge device which is actuated and can be activated by the electronic control unit. It is useful for the spring element to be separated to extend slightly over the separation tools in the forward direction so that it can be easily reached by the discharge device. The spring steel strip is wrapped around a stock roll, and the diameter of the stock roll and therefore the pre-curvature of the spring steel strip changes during production. In order that the bending unit can largely meet the same prerequisites, it is suggested that a preliminary bending unit be provided before the bending unit. This is so controlled, depending on the diameter of the stock roll and, for example, the thickness of the spring steel strip, that during production, regardless of the diameter of the changing stock roll, conditions are produced. equal input at the bend station.

For the production of spring elements, more processing steps are often required, eg labeling or tagging. In order to be able to carry out these processing steps in the same production process it is appropriate to have in front of the bending unit a processing unit whose tools can be moved in a longitudinal direction and which during the duration of use are synchronized. with forward motion. These tools that necessarily condition an interruption of the forward movement, can thus be used without an interruption of the forward movement of the spring steel strip.

Drawing

Other advantages are apparent from the following description of the design. In the drawing, examples of implementation of the present invention are shown. The design, description and claims contain numerous combined features. The person skilled in the art will also consider the characteristics separately and assemble them for further useful combinations.

They show:

Figure 1 shows a schematic presentation of a device according to the present invention.

Figure 2 shows a variation of figure 1.

Description of Execution Examples

A device 10 according to the present invention essentially comprises a feed unit 16, a bend unit 32, and a separation unit 44. The feed unit 16 has at least two feed rollers 18 opposite each other. another is a spring-loaded steel strip 14. The feed rollers 18 are positioned and driven by an adjusting device 28 and convey the spring steel strip 14 from a stock roll 12 to the feed roller. bending unit 32. Therein, three bending rollers 34 are arranged in such a manner relative to each other that the spring steel strip 14 is bent to a predetermined bend. At least one of the bending rollers 34 may be adjusted transversely to the longitudinal direction 52 of the spring steel strip 14 so that the bending flexure may be altered. In the forward direction 72 of the spring steel strip 14 follows after the three bending rollers 34 a rewind roll 36 which can be adjusted transversely to the longitudinal direction 52 of the spring steel strip 14 by means of an adjusting device 40. Through bending roll 36, spring steel strip 14 is bent in a reverse direction by a certain amount in order to provide the finished product with greater stability. The bending of the spring steel strip 14 is taken into account by a stronger forward bending in the three bending rollers 34 respectively.

In the next separation unit 44, a finished curved spring element is separated from the spring steel strip 14 by an upper separation tool 46 and a lower separation tool 48. For easier separation, the spring element is elastically pressed to be straightened by guide rollers 50. The separating tools 46, 48 are longitudinally displaceable 52 so that their cutting edges may move longitudinally 52 relative to the steel strip for springs 14. During the cutting movement of the separation tools 46, 48 the longitudinal movement of the separation tools 46, 48 is synchronized with the forward movement of the spring steel strip 14 so that a cutting is possible. need. The movements of the separation tools 46, 48 and the curving rollers 34, 36 and the feed rollers 18 are coordinated via an electronic control unit 42 depending on relevant process parameters. To compensate for the dynamic mass forces in handling the separation tools 46, 48, it is useful to provide opposite motion compensation masses for the separation tools 46, 48. The constant operation of the separation tools 46, 48 exerts a favorable influence on the guide and the advance of the spring steel strip 14.

The separation tools 46, 48 may be adjusted together with the separation unit in longitudinal direction 52 with respect to a housing 54 (Figure 2). According to the setting of the separating tools 46, 48, the guide rollers 50 modify the distances from one another so that they are distributed more or less evenly along the guide track.

Between the feeder unit 16 and the bend unit 32 there is provided a bender unit 20 comprising three bend rollers 22 of which one can be adjusted via an adjusting device 30 transversely to the longitudinal direction 52 of the tape. spring steel 14. Adjustment is made by the electronic control unit 42 depending on the diameter 24 of the stock roll 12 and the thickness 26 of the spring steel tape 14. The pre-bending unit 20 compensates with simple means. different degrees of curvature of the spring steel strip 14 due to the different diameters 24 during the production process, so that an expensive straightening device can be dispensed with.

In the embodiment according to FIG. 2, the feed unit 16, the bend unit 32 and two measuring wheels NC 56, 58 are joined to form a construction unit 90 which is adjustable in longitudinal direction 52 and may change its position in relation to the separation unit 44. The adjustment of the construction unit 90 can be done manually. But it can also be motor driven by a spindle drive, and the adjustment path can be part of an automatic preparation process. Using the measuring wheel NC 56, the slip of the pulled spring steel strip 14 is measured, and using the measuring wheel NC 58, the slip of the pushed spring steel tape 14 is measured. The measuring wheels 56, 58 precisely capture the feed, and the second measuring wheel 58 monitors the first measuring wheel 56 and the transport portion between them. It is advantageous when the second measuring wheel 58 is disposed on the outer side of the housing 54 of the separation unit 44.

In the bending unit 32, the upper bending roll 34 is supported on a bend roll holder 70 which can be adjusted through a spindle 66 by a bend motor 62. The bend roll 36 is supported on a roll holder bend 68, where the bend roll holder 68 is adjusted by a bend motor 60 through a spindle 64. The adjustment of these adjusting devices is very precise and almost free of play.

Between the bending unit 32 and the separation unit 44 the spring steel strip 14 is guided by a roller guide 74 whose guide rollers can be pneumatically adjusted to the spring steel strip 14.

The separating unit 44 according to FIG. 2 is formed by a press, whose upper stamping tool 76 is mounted on an upper tool carriage 80 which is slidably guided in a box 54 of the separating unit 44 in longitudinal direction. 52 by means of carriage guides 84, 86. Accordingly, a lower crimping tool 78 is mounted on a lower tool carriage 82 which is in turn displaceablely guided on a carriage guide 86 towards - longitudinal section 52 in the housing 54. Since the guide rollers 50 in the stamping tool area 76, 78 need to overcome a different guide portion depending on which position the stamping tools 76, 78 are in, can be separated like a telescope, so that depending on the position of the stamping tools 76, 78 greater or shorter distances appear between the guide rollers 50. The stamping tools 76, 78 which in the present case works m as separation tools can also act in conjunction with compensation masses.

In forward direction 72 at the end of the device 10 is a discharge device 88 which is actuated and can be activated by the electronic control unit 42. It reaches the end of the finished curved spring element protruding out of the stamping tools 76, 78, and after separation deposit it into a reservoir.

Claims (20)

1. Method for producing curved spring elements from a spring steel strip (14), wherein a feed unit (16) carries the spring steel strip (14) from a stock roll (12) ) for a bending unit (32) with at least three bending rollers (34) and a bend roll (36), of which at least one bend roll (34) and bend roll (36) can be adjusted. bending motors (60, 62) transversely to the spring steel strip (14), and the bending unit (32) is followed by a separating unit (44) which cuts the spring steel strip ( 14) by means of separation tools (46, 48; 76, 68) for obtaining various spring elements, characterized in that the separation tools (46, 48; 76, 78) can be moved longitudinally spring-controlled steel strip (14) and during the separation process are synchronized with the forward movement of the steel strip for springs (14). Device (10) for carrying out the method according to claim 1, with a stock roll (12), a bending unit (32) and a separation unit (44) having an upper separation tool ( 46) and a lower parting tool (48) between which the spring steel strip (14) passes, characterized in that the parting tools (46, 48; 76, 78) are arranged in longitudinal direction. - nal (52) of the forward movement of the spring steel strip (14) in an adjustable manner relative thereto, and its adjusting movement is synchronized via an electronic control unit (42) during processing. of separation with the forward movement of the spring steel strip (14). Device (10) according to claim 2, characterized in that the separating tools (46, 48; 76, 78) together with the separating unit (44) can be adjusted longitudinally (52). ) of the forward movement of the spring steel strip (14) relative thereto. Device (10) according to claim 2, characterized in that the separation tools (46, 48; 76, 78) are arranged in a stationary box (54) of the separation unit (44). ) where they may be adjusted relative to the housing (54) and longitudinally (52) of the forward movement of the spring steel strip (14) relative thereto. Device (10) according to claim 4, characterized in that the separation tools are an upper stamping tool (76) and a lower stamping tool (78) which are mounted on an upper carriage. (80) or a lower tool carriage (82), with the tool carriage (80, 82) being guided longitudinally (54) into carriage guides (84, 86) in the housing (52) . Device (10) according to one of claims 4 or 5, characterized in that to compensate for the dynamic mass forces during the operation of the separation tools (46, 48; 76, 78), masses of compensation in opposite motion. Device (10) according to one of Claims 2 to 6, characterized in that after the bending unit (32) a roller guide (74) is provided, the rollers of which can be pneumatically adjusted to the spring steel strip. (14). Device (10) according to claim 7, characterized in that some guide rollers (50) in the area of the separating tools (46, 48; 76, 78) may change their position towards each other towards each other. such that their distances from one another increase or decrease depending on the movement of the separation tools (46, 48; 76, 78) in the longitudinal direction (52). Device (10) according to one of the preceding claims, characterized in that the separation unit (44) is followed by the discharge device (88) which is actuated and can be activated by the electronic control unit ( 42). Device (10) according to one of Claims 2 to 9, characterized in that at least one of the bending rollers (34) is supported by a bending roll holder (70) and the bending roll (36). ) in a bend roll holder (68), wherein the bend roll holders (68, 70) are adjusted by bend motors (60, 62) through spindles (64, 66). Device (10) according to claim 10, characterized in that the bending motors (60, 62) are GBC bending motors, with the travel path of the bending roll holders ( 68, 70) are determined by taking into account the set values of the electronic control unit (42) via a rotating incremental transmitter. Device (10) according to claim 10, characterized in that the bending motors (60, 62) are linear motors. Device (10) according to Claim 11 or 12, characterized in that the travel path of the bending roll holders (68, 70) is determined by an integrated absolute measuring value transmitter. through software. Device (10) according to claim 13, characterized in that the absolute measured value emitter comprises a glass scale with a sensor. Device (10) according to one of Claims 2 to 14, characterized in that τΓ bending unit (32), feed unit (16) and at least one NC measuring wheel (56, 58). are assembled to form a longitudinally displaceable construction unit (90) (52). Device (10) according to claim 14, characterized in that two NC measuring wheels (56, 58) are provided, a first of which (56) is arranged in forward direction (72) prior to bending unit (32) and a second (58) after the bending unit (32). Device (10) according to claim 16, characterized in that the second NC measuring wheel (58) is arranged in the housing (54) of the separation unit (44). Device (10) according to one of Claims 15 to 17, characterized in that the mounting unit (90) can be adjusted by motor via a motorized spindle drive, the adjustment process being part of an automatic preparation process. Device (10) according to one of the preceding claims, characterized in that a pre-bending unit (20) is provided prior to the bending unit (32). Device (10) according to one of the preceding claims, characterized in that a processing unit is arranged prior to the bending unit (32) for labeling or tagging, the tooling of which can be moved towards it. (52) and which during use time are synchronized with the forward movement.